Orbit Determination Using Satellite-to-Satellite Tracking Data

Satellite-to-Satellite tricking (SST) data can be used to determine the orbits of spacecraft in two ways. One is combined orbit determination, which combines SST data with ground-based tracking data and exploits the enhanced tracking geometry. The other is the autonomous orbit determination, which uses only SST. The latter only fits some particular circumstances since it suffers the rank defect problem in other circumstances. The proof of this statement is presented. The nature of the problem is also investigated in order to find an effective solution. Several. methods of solution are discussed. The feasibility of the methods is demonstrated by their application to a simulation.

Research on a Velocity Determination and FDE Algorithm for High-Dynamic GNSS Receiver

A velocity determination algorithm of GNSS receiver for high speed and high acceleration carrier in motion is mainly discussed in this paper. For this algorithm, the Doppler frequency value is extracted from the satellite carrier tracking loop, and(α, β, γ) filter is adopted for smoothing, and least square is adopted to calculate the receiver speed and local clock drift. To get accurate determination value, a kind of fault detection and exclusion technology(FDE) is designed in this paper; the satellite Doppler frequency value with large error is detected and exclusion. Finally, the signal of GNSS signal simulator and actual navigational satellite signal are received for test, getting good velocity determination result.

A Highly Sensitive and Selective Spectrofluorimetric Method for the Determination of Arsenic at Pico-Trace Levels in Some Groundwater, Real, Environmental, Biological, Food and Soil Samples Using 2-(<i>α</i>-Pyridyl)-Thioquinaldinamide

A very simple, ultra-sensitive, highly selective and non-extractive new spectrofluorimetric method for the determination of arsenic at pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been developed. PTQA has been proposed as a new analytical reagent for the direct non-extractive spectrofluorimetric determination of Arsenic (V). This novel fluorimetric reagent, PTQA becomes oxidized in a slightly acidic (0.025 - 0.1 M H2SO4) solution with Arsenic (V) in absolute ethanol to produce highly fluorescent oxidized product (λex = 303 nm;λem = 365 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.025 - 0.1 M H2SO4) for the period between 2 min and 24 h. Linear calibration graphs were obtained for 0.001 - 800-μgL-1 of As, having a detection limit of 0.1-ngL-1;the quantification limit of the reaction system was found to be 1-ngL-1 and the RSD was 0% - 2%. A large excess of over 60 cations, anions and complexion agents (like, chloride, phosphate, azide, tartrate, oxalate, SCN, etc.) do not interfere in the determination. The developed method was successfully used in the determination of arsenic in several Certified Reference Materials (alloys, steels, ores, human urine, hair, nails, bovine liver and sediments) as well as in some biological fluids (human blood, urine, hair, nail and milk), soil samples, food samples (vegetables, fruits, rice, corn and wheat), solutions containing both arsenic (III) and arsenic (V) speciation and complex synthetic mixtures. The results of the proposed method for assessing biological, food and soil samples were comparable with both ICP-OES & AHG-AAS and were found to be in excellent agreement.

Determination of Cationic Surfactant by Laser Thermal Lens Spectrometry

A novel method for the determination of cationic surfactant by laser thermal lens spectrometry was developed. It was based on the reaction between 1-hydroxy-2-(5-nitro-2-Pyri- dylazo)-8-aminonaphthalene-3,6-disulfonic acid (5-NO2-PAH) and cationic surfactant to form 1:2 ionic association complex in a weakly basic medium (pH 9.44). The determination conditions and the mechanism were discussed. The method has been applied to the analysis of wastewater and moat water samples.

4-氨基安替比林光度法测定啫喱水中的甲萘酚

在碱性条件下,采用高碘酸钾为氧化剂,4-氨基安替比林(4-AAP)为显色剂,用分光光度法测定不同品牌啫喱水中甲萘酚的含量。实验最佳条件为:波长为500 nm,氧化剂用量为5.50 mL,缓冲液的用量4.50 mL,缓冲液的pH为10.0,显色剂用量为4.50 mL,常温反应10 min。结果表明:甲萘酚在0.2~8.0 mg/L范围内,呈良好线性关系,标准曲线为A=0.062c-0.004,相关系数R^(2)=0.999,平均回收率为99.2%。

化学计量学-荧光分析法同时测定萘、1-萘酚和2-萘酚

根据正交信号校正(OSC)、小波包变换(WPT)及偏最小二乘法(PLS)的算法原理,编制了名为POSCWPTPLS的程序,结合荧光分析法快速、灵敏、选择性较好的优点,将该程序用于同时测定荧光光谱严重重叠的萘、1-萘酚和2-萘酚多组分体系,并将3种化学计量学方法(OSC-WPT-PLS、WPT-PLS和PLS)进行比较。3种化合物的总相对预测标准偏差分别为3.3%,5.9%和6.7%。结果表明:OSC-WPT-PLS法优于WPT-PLS和PLS法。将本方法用于自来水及两种废水的分析,取得了良好的效果,回收率分别为97.4%～102.7%,98.8%～100.7%和98.1%～104.6%。

导数荧光光谱法同时测定α-萘酚和β-萘酚异构体的研究

将导数荧光光谱法用于异构体分析，提出了直接同时测定α－萘酚和β－萘酚的新方法。在ｐＨ９．１８缓冲体系中，室温下进行一阶导数荧光检测α－萘酚和β－萘酚的检出限分别为０．０１３ｎｇ／ｍｌ和０．０１１ｎｇ／ｍｌ，精密度（ＲＳＤ）分别为１．７％和１．４％。该法用于合成样品中α－萘酚和β－萘酚的同时测定，回收率在９５．４％～１０４％以内。

α-萘酚法定量测定L-Arg的研究

研究了用坂口试剂— α-萘酚定量测定 L- Arg的方法。确立了 L- Arg水溶液和发酵液L- Arg含量测定的最佳条件分别为 :(1) 0 .0 12 5 mol/ L Na OH0 .8m L、0 .0 0 138mol/ Lα-萘酚90μL、Na Cl O 12 0μL ,40℃水浴显色 15 min后 ,于室温下 40 min内测定 ;(2 ) 0 .0 12 5 mol/ LNa OH 0 .8m L、0 .0 0 138mol/ Lα-萘酚 15 0μL、Na Cl O 2 80μL ,40℃水浴显色 5 min后置于冰水混合物中 ,40 min内测定。根据发酵液 L- Arg测定标准曲线 ,推导出其 L- Arg含量的计算公式为 :X=117.6 5×A×N。

铑-1-(2-吡啶偶氮)萘酚络合吸附波测定微量铑

铑和 1- (2 -吡啶偶氮 )萘酚 (PAN)在 p H=5.0 0的邻苯二甲酸氢钾—氢氧化钠介质中生成具有电活性的络合物 ,在单扫示波极谱 - 0 .6 7V(vs.SCE)处呈现良好极谱还原波 .该波二阶导数峰高与铑的浓度在 2 .3× 10 -8～ 4 .8× 10 -7mol· L-1和 4 .8× 10 -7～ 9.7× 10 -6mol· L-1范围内呈线性关系 ,检出限为 7.6× 10 -9mol· L-1,并成功的用于贵金属合成样及合金样品中铑含量的测定 .

1-(5-溴-2-吡啶偶氮)-2-萘酚-6-磺酸作指示剂络合滴定连续测定铜和锌

对５－Ｂｒ－ＰＡＮ－Ｓ作指示剂络合滴定连续测定铜和锌进行了研究。在 ｐＨ ６．０的乙酸－乙酸钠介质中，以５－Ｂｒ－ＰＡＮ－Ｓ作指示剂，ＥＤＴＡ为滴定剂连续测定铜和锌，滴定终点颜色变化敏锐，准确度高，铜和锌量各在０～２０ｍｇ范围内与ＥＤＴＡ用量成正比，铜、锌比例在１：１０－１０：１范围内相互无影响。方法用于合金中铜、锌的连续测定，结果满意。

α-萘酚的电化学性质及示差脉冲伏安法测定

研究α-萘酚在玻碳电极上的电化学性质.在pH=7.0的Britton-Robinson缓冲溶液中,α-萘酚在玻碳电极上发生不可逆的氧化反应,氧化峰电位为0.25 V.用循环伏安法考察了其电化学氧化机理,建立了测定α-萘酚的示差脉冲伏安法.α-萘酚的浓度在1.0～8.0×102μmol/L范围内与氧化峰电流呈线性关系,测定结果的相对标准偏差为2.99%,加标回收率为97.0%～103.5%.

PAN-6S作络合滴定指示剂连续测定铜和镍的研究

就PAN 6S试剂作络合滴定指示剂连续测定铜和镍进行研究.在pH为2.3的氨基乙酸 盐酸溶液中,以PAN 6S作指示剂,以EDTA为滴定剂连续滴定测定镍和铜,其终点颜色变化敏锐,准确度高,铜、镍比例在1∶20～20∶1范围之间相互无影响.方法用于合金中铜、镍的连续测定,结果满意.

Precise orbit determination for TH02-02 satellites based on BDS3 and GPS observations

The Tianhui-202(TH02-02)satellite formation,as a supplement to the microwave mapping satellite system Tianhui-201(TH02-01),is the first Interferometric Synthetic Aperture Radar(InSAR)satellite formation-flying system that supports the tracking of BeiDou global navigation Satellite system(BDS3)new B1C and B2a signals.Meanwhile,the twin TH02-02 satellites also support the tracking of Global Positioning System(GPS)L1&L2 and BDS B1I&B3I signals.As the spaceborne receiver employs two independent boards to track the Global Navigation Satellite System(GNSS)satellites,we design an orbit determination strategy by estimating independent receiver clock offsets epoch by epoch for each GNSS to realize the multi-GNSS data fusion from different boards.The performance of the spaceborne receiver is evaluated and the contribution of BDS3 to the kinematic and reduced-dynamic Precise Orbit Determination(POD)of TH02-02 satellites is investigated.The tracking data onboard shows that the average number of available BDS3 and GPS satellites are 8.7 and 9.1,respectively.The carrier-to-noise ratio and carrier phase noise of BDS3 B1C and B2a signals are comparable to those of GPS.However,strong azimuth-related systematic biases are recognized in the pseudorange multipath errors of B1C and B3I.The pseudorange noise of BDS3 signals is better than that of GPS after eliminating the multipath errors from specific signals.Taking the GPS-based reduced-dynamic orbit with single-receiver ambiguity fixing technique as a reference,the results of BDS3-only and BDS3+GPS combined POD are assessed.The Root Mean Square(RMS)of orbit comparison of BDS3-based kinematic and reduced-dynamic POD with reference orbit are better than 7 cm and 3 cm in three-Dimensional direction(3D).The POD performance based on B1C&B2a data is comparable to that based on B1I&B3I.The precision of BDS3+GPS combined kinematic orbit can reach up to 3 cm(3D RMS),which has a more than 25%improvement relative to the GPS-only solution.In addition,the consistency between the BDS3+GPS combined reduced-dynamic orbit and the GPS-based ambiguity-fixed orbit is better than 1.5 cm(3D RMS).

高效液相色谱法测定盐酸度洛西汀肠溶胶囊中α-萘酚杂质含量

目的建立用于盐酸度洛西汀肠溶胶囊中α-萘酚杂质测定的高效液相色谱（HPLC）法。方法色谱柱为Agilent C8柱（150 mm×4.6 mm,3.5μm）,流动相为乙腈-正丙醇-缓冲液（配制2.9 g/L磷酸溶液,用氢氧化钠溶液调节pH至2.5,取该溶液1 L,加入10.3 g一水己烷磺酸钠,摇匀,使完全溶解,13∶17∶70）,流速为1.0 mL/min,检测波长为230 nm,柱温为40℃。结果α-萘酚的进样量在8×10^-4-8×10^-3μg范围内与峰面积呈良好的线性关系（r=0.997 6）,平均回收率为99.25%,RSD为0.89%（n=9）。结论该法专属性强、耐用、准确,可用于盐酸度洛西汀肠溶胶囊中α-萘酚的测定。

1-(5-溴-2吡啶偶氮)-2-萘酚-6-磺酸作指示剂络合滴定连续测定铝和钛

在酸性溶液中加入对铝、钛过量的EDTA标准溶液，在pH4．0煮沸下，铝（Ⅲ）、钛（Ⅳ）与EDTA生成稳定的络合物。以5-Br-PAN-S作指示剂，用硫酸铜标准溶液返滴定过量的EDTA，测定铝钛合量，再用置换法测定钛的量。终点变色敏锐，准确度高，方法用于硅酸盐矿物中铝钛的连续测定，结果满意。

LC-MS测定C^(13)尿素同位素丰度方法的建立

13C-尿素呼气试验(13C-UBT)是采用C13尿素在临床上诊断幽门螺杆菌(Hp)的一种无创性方法[1],具有高效、灵敏度高、特异性强和使用安全等特点,被认为是除组织培养以外的诊断Hp的"金标准",在临床上已被广泛应用[2].……

Culm characteristics and volume-weight relationship of a forest bamboo(Melocanna baccifera(Roxb.) Kurz) from northeast India

Culm characteristics of Melocanna baccifera, locally ＇muli＇, culms at five different culm ages of 11 girth classes （5-6 to 15-16 cm） were studied from Cachar Dis- trict of southern Assam, northeast India. We recorded internode length, internode diameter, number of internodes per culm, total culm height, total culm green weight and total culm volume of all five culm age classes. Data were gathered on 165 culms, each culm age class containing 33 culms with 3 culms per girth class. Culm height ranged from 3.2 to 15.3 m with highest mean of 9.15 m （in threeyear old culms） and maximum culm height was recorded in four-year old culms. Highest mean and maximum internode length （27.45 and 54.2 cm, respectively）, internode diameter （3.12 and 4.75 cm, respectively） and total culm green weight （5.42 and 12.87 kg/culm, respectively） were recorded in three-year old culms and lowest in current-year culms. Best fitted regression models for all parameters were developed. Significant linear relationships between culm green weight and culm solid volume were documented for all five culm age classes. Their corresponding best-fit regression models were also developed.

Polarographic behavior of 1,4,7-triazacycloanane-N,N',N"-tris (meth-ylphonic acid) (NOTP)-Bi(Ⅲ) complex

The polargraphic behavior of Bi(Ⅲ)-NOTP complex has been investigated inaqueous solution. It was found that under the conditions of pH 3.0 and of 0.02 mol/L NH_4Cl, theBi(Ⅲ)-NOTP system gives a sensitive second order derivative wave at -0.340 V(vs SCE), which isproved to be an adsorptive complex wave. The composition of the complex is Bi(Ⅲ):NOTP. Furthermore,the peak current is linear to the concentration of Bi(Ⅲ) in the range from 3.0x10^(-8) to5.0x10^(-6) mol/L. Artificial and practical samples have been detected with high sensitivity andreceptivity.

Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether

Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.

An Ultrastable π-π Stacked Porous Organic Molecular Framework as a Crystalline Sponge for Rapid Molecular Structure Determination

The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of guests,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.